User's Manual

Pre–Power–up Tests

68P09258A31–A

Oct 2003

1X SCt 4812T BTS Optimization/ATP

2-12

DC Power Pre-test (RFDS)

Before applying power to the RFDS, follow the steps in Table 2-3, while

referring to Figure 2-7, to verify there are no shorts in the RFDS DC

distribution system, backplanes, or modules/boards. As of the date of

this publication, the RFDS is not used with the –48 V BTS.

NOTE

Visual inspection of card placement and equipage for each frame

vs. site documentation must be completed, as covered in

Table 2-1 on page 2-3, before proceeding with this test.

Table 2-3: DC Power Pre-test (RFDS)

Step Action

1 Physically verify that all DC/DC converters supplying the RFDS are OFF or disabled.

2 Set the input power rocker switch P1 to the OFF position (see Figure 2-7).

3 Verify the initial resistance from the power (+ or –) feed terminal with respect to ground terminal

measures >

5 kΩ , then slowly begins to increase.

S If the initial reading is < 5 kΩ and remains constant, a short exists somewhere in the DC

distribution path supplied by the breaker. Isolate the problem before proceeding.

4 Set the input power rocker switch P1 to the ON position.

Repeat Step 3.

Figure 2-7: DC Distribution Pre-test (COBRA RFDS Detail)

NOTE:

Set the input power switch ON while measuring the

resistance from the DC power – with respect to the

power + terminal on the rear of the COBRA RFDS.

INPUT POWER

SWITCH (P1)

FRONT OF COBRA RFDS

(cut away view shown for clarity)

RFDS REAR

INTERCONNECT PANEL

“–” CONNECTOR

“+” CONNECTOR

CONNECTOR (MADE

UP OF A HOUSING

AND TWO PINS)

FW00139